diff --git a/Gemfile.lock b/Gemfile.lock
index 161485f..eb0210b 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -16,7 +16,7 @@ PATH
       kramdown-haml
       puma
       rails (= 4.1.4)
-      rubyzip
+      rubyzip (~> 1.1)
       sass-rails (~> 4.0.3)
       settingslogic
       sucker_punch (~> 1.0.5)
diff --git a/fluentd-ui.gemspec b/fluentd-ui.gemspec
index 9961e7f..63b67f9 100644
--- a/fluentd-ui.gemspec
+++ b/fluentd-ui.gemspec
@@ -36,5 +36,5 @@ Gem::Specification.new do |spec|
   spec.add_dependency "thor"
   spec.add_dependency "kramdown", "> 1.0.0"
   spec.add_dependency "kramdown-haml"
-  spec.add_dependency "rubyzip"
+  spec.add_dependency "rubyzip", "~> 1.1" # API changed as Zip::ZipFile -> Zip::File since v1.0.0
 end